CN101136609A - Amplifier apparatus and method - Google Patents
Amplifier apparatus and method Download PDFInfo
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- CN101136609A CN101136609A CNA2007101476176A CN200710147617A CN101136609A CN 101136609 A CN101136609 A CN 101136609A CN A2007101476176 A CNA2007101476176 A CN A2007101476176A CN 200710147617 A CN200710147617 A CN 200710147617A CN 101136609 A CN101136609 A CN 101136609A
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- 230000005236 sound signal Effects 0.000 description 4
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- 206010047700 Vomiting Diseases 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 230000008673 vomiting Effects 0.000 description 3
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- GOLXNESZZPUPJE-UHFFFAOYSA-N spiromesifen Chemical compound CC1=CC(C)=CC(C)=C1C(C(O1)=O)=C(OC(=O)CC(C)(C)C)C11CCCC1 GOLXNESZZPUPJE-UHFFFAOYSA-N 0.000 description 1
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/30—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters
- H03F1/305—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters in case of switching on or off of a power supply
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/181—Low-frequency amplifiers, e.g. audio preamplifiers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/45—Differential amplifiers
- H03F3/45071—Differential amplifiers with semiconductor devices only
- H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
- H03F3/45475—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using IC blocks as the active amplifying circuit
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/34—Muting amplifier when no signal is present or when only weak signals are present, or caused by the presence of noise signals, e.g. squelch systems
- H03G3/348—Muting in response to a mechanical action or to power supply variations, e.g. during tuning; Click removal circuits
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/03—Indexing scheme relating to amplifiers the amplifier being designed for audio applications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
- H03F2203/45—Indexing scheme relating to differential amplifiers
- H03F2203/45138—Two or more differential amplifiers in IC-block form are combined, e.g. measuring amplifiers
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- Power Engineering (AREA)
- Multimedia (AREA)
- Amplifiers (AREA)
Abstract
The invention concerns the suppression of audible 'pop' or 'click' when switching off an audio amplifier. The invention is characterised by the use of a discharge circuit 150 for controlling the operation of a reference voltage (mid-rail) generator 13 during power-down. The reference voltage generator circuit includes a decoupling capacitor 135. The discharge control circuit includes an amplifier 151 with a positive feedback path for controlling current flow from the capacitor during power-down. The exponential fall of the mid-rail voltage (4) is rendered into a smooth S-shaped curve (6), avoiding a sharp discontinuity at the moment of turn-off.
Description
Technical field
The present invention relates to reduce the amplifier installation and the method for unwanted transient signal, and relate more specifically to reduce the amplifier breaker device and the method for the unwanted earcon that produces by transient signal in the audio-frequency amplifier circuit.
Background technology
" noise made in coughing or vomiting clatter " and " crack " be to be used to describe when audio frequency amplifier cuts off the power supply, the term of the unwanted audio frequency transient signal of in earphone or loud speaker, hearing.
In portable audio was used, power consumption was a key issue, and this just means when unwanted the time, the usually disabled or outage such as the circuit element of audio frequency amplifier.This may cause when audio frequency amplifier is de-energized or places static or park mode, produces unwanted audio frequency transient signal.In other non-portable use also similar problem may take place.
Noise made in coughing or vomiting clatter and crack problem are especially outstanding in single power amplifier, and single power amplifier must be charged to a certain assigned voltage during powering up, then must discharge between turnoff time.
Fig. 1 shows the known audio-frequency amplifier circuit 1 that the load 2 of for example earphone of output 3 or loud speaker is coupled in a kind of driving.Output amplifier 5 at first input end 7 from audio-source received audio signal such as frequency mixer 9.Should be appreciated that frequency mixer 9 is from DAC (not shown) or other signal source received audio signal.Amplifier 5 also receives reference voltage V at second input 11
MIDFor the output signal that makes amplifier reaches peak swing in every side of its quiescent output voltage, this quiescent voltage is set at the centre on supply voltage VDD and ground (GND).This quiescent voltage is to pass through the reference voltage V that applied
MIDBe provided with, it equals VDD/2.
Reference voltage V
MIDProduce by reference voltage generator circuit 13.As described in more detail below, when output amplifier 5 is de-energized, may produce transient signal, thereby make unwanted " crack " be transferred to earphone or loud speaker.
Should be noted that provides control logic 10 to be used for the operation of control amplifier circuit 1 during various operator schemes.For example, control logic 10 is provided for controlling the control signal S with reference to generator circuit 13
1, be used to control the control signal S of output amplifier 5
2(for example when carrying out quiet (mute) operation) and the control signal S that is used to control buffer circuit 14
3The reference voltage V that buffer circuit 14 bufferings receive from reference voltage generator circuit 13
MIDShould be noted that buffer circuit is not that the amplifier circuit operation is necessary.
Fig. 2 explanation is used for the example of the power down sequence of audio frequency amplifier according to prior art.First step, step 201 relates to the control signal S by control logic 10
2Make output amplifier 5 quiet.In noise-limited condition, this output is not subjected to the influence of this input signal, for example by using switch to come the interrupt signal path.Then, up (upstream) circuit unit of output amplifier 5 is disabled, and for example, frequency mixer 9, DAC (not shown) etc. are disabled, step 203.After this up loop forbidding, produce this reference voltage V
MIDThis reference voltage generator circuit 13 then disabled, step 205.This is for example by using the control signal S from this control logic 10
1Opening the switch 131 of Fig. 1 carries out.
This reference voltage V
MIDDrop to 0v a delay, step 207 are arranged.According to the whole capacitor load, this postpones nearly 1 second.In case this reference voltage V
MIDDrop to 0v, this output amplifier 5 is followed disabled or outage, step 209.
When carrying out, as reference voltage V such as above-mentioned power down sequence
MIDWhen beginning to be discharged to zero (ground), can hear " crack ", further to describe as following.
Fig. 3 shows and is used to produce reference voltage V
MIDReference voltage generator circuit 13.Use and for example comprise that the bleeder circuit of resistance element 137 and 139 can produce this reference voltage V
MIDIf selecting the voltage levvl of reference voltage is VDD/2, resistance element 137 and 139 will have equal value so.Should be appreciated that resistance element 137 will have different values with 139 so if require different reference voltages.Decoupling capacitance device 135 is connected to the two ends of resistance element 139.Should be noted that if desired, decoupling capacitance device 135 can provide, and is used for decoupling zero V under the situation of integrated circuit configuration outside sheet
MIDNode 133.Provide one at control signal S
1Control start down and the switch 131 of forbidding reference voltage generator circuit 13.
Fig. 4 shows the reference voltage V in amplifier circuit 1 turnoff time intermediate node 133
MIDFor example reference voltage generator circuit 13 is being switched to T by opening switch 131
OFFThe time, capacitor 135 is by resistance 139 discharges.This just causes reference voltage V
MIDAt T
OFFSlope discontinuity (slope discontinuity) or fast skew.When decoupling capacitance device 135 continues discharge, described reference voltage V
MIDThe decline of voltage levvl become slower, discharge fully up to decoupling capacitance device 135.Reference voltage V
MIDAt T
OFFThis slope discontinuity constantly produces by capacitor 15 and propagates into earcon composition in the load, and therefore also caused audio frequency crack.
A kind of method of avoiding these slope discontinuities is the value that increases resistance 139.Yet, because the value that depends on resistance 139 total time of capacitor 135 discharges so increase the value of resistance 139 the guiding discharge time is looked unacceptable (several seconds), and is the hundreds of millisecond desirable discharge time.
Therefore, the objective of the invention is to, a kind of amplifier breaker device and method that reduces unwanted signal in the voicefrequency circuit is provided.
Summary of the invention
According to a first aspect of the invention, a kind of amplifier breaker device that is used for reducing the voicefrequency circuit transient signal is provided, this voicefrequency circuit comprises the reference voltage generator circuit that is used to produce reference voltage, and this reference voltage generator circuit comprises the capacitor that is used for reference voltage is maintained the expectation voltage levvl.This device comprises the charge/discharge control circuit that is used to control the operation between the reference voltage generator circuit turnoff time.This charge/discharge control circuit comprises the amplifier with positive feedback path that is used to control from the electric current of capacitor.
This amplifier breaker device has the advantage that reduction can be listened transient signal between the audio frequency amplifier turnoff time.
According to another aspect of the present invention, a kind of method that is used for reducing the voicefrequency circuit transient signal is provided, this voicefrequency circuit comprises the reference voltage generator circuit that is used to produce reference voltage, and this reference voltage generator circuit comprises the capacitor that is used for reference voltage is maintained the expectation voltage levvl.This method may further comprise the steps: be provided for controlling the charge/discharge control circuit of reference voltage generator circuit outage manipulate, and use has the electric current of the amplifier control of positive feedback path from the capacitor of reference voltage generator circuit.
According to other aspects of the invention, the various systems that adopt amplifier breaker device defined in the appended claims are provided.They include but not limited to audio devices, portable audio, Earphone Amplifier, headphone, communicator (for example, mobile phone) and audio device in car.
Description of drawings
In order to understand the present invention better, and more clearly illustrate how to be applied to reality, only the mode by embodiment is described with reference to following accompanying drawing now, wherein:
Fig. 1 shows the voicefrequency circuit according to prior art;
Fig. 2 has described the typical power down sequence that is used for circuit shown in Figure 1;
Fig. 3 shows the reference voltage generator circuit according to prior art;
Fig. 4 curve chart is illustrated in the prior art circuits, and how reference voltage discharges between turnoff time;
Fig. 5 shows the reference voltage generator circuit with amplifier breaker device according to first embodiment of the invention;
Fig. 6 shows the device that uses Fig. 5, and how reference voltage discharges;
Fig. 7 shows the reference voltage generator circuit with amplifier breaker device according to second embodiment of the invention;
Fig. 8 shows the example that typical case of the present invention uses;
Fig. 9 shows the other example that typical case of the present invention uses;
Figure 10 shows the other example that typical case of the present invention uses; And
Figure 11 shows the other example that typical case of the present invention uses.
Embodiment
Fig. 5 shows the amplifier breaker device that is used for reducing the voicefrequency circuit undesired signal according to embodiments of the present invention.Similar with the mode among Fig. 3, be used to produce reference voltage V
MIDReference voltage generator circuit 13 comprise bleeder circuit, this bleeder circuit comprises resistance element 137 and 139.Can select resistance element 137 and 139, for example to provide the supply main that is positioned at VDD and ground middle reference voltage.Decoupling capacitance device 135 is connected the two ends of resistance element 139.Decoupling capacitance device 135 can provide outside sheet, if desired, also is used for decoupling zero V
MIDNode 133.For example providing, the transistorized switch 131 of PMOS is used for starting and forbidding reference voltage generator circuit 13.
Yet, as described below, be not only to use switch 131 to forbid or the reference voltage generator circuit 13 that cuts off the power supply, the amplifier breaker device comprises and being provided for controlled manner reference voltage V
MIDThe charge/discharge control circuit 150 of discharge.
Suppose that decoupling capacitance device 135 is at moment t
OFFCharging fully before, the voltage of node 133 will be V so
MIDAs described below, charge/discharge control circuit 150 control reference voltage V
MIDDischarge.
Charge/discharge control circuit 150 comprises the amplifier such as differential amplifier 151 that is built into positive feedback configuration.Connect differential amplifier 151 to receive the reference voltage V of its negative input end
MID, with and " manually " reference voltage V of positive terminal
MIDAThis artificial reference voltage V
MIDABe to use the bleeder circuit that comprises resistance 157 and 158 to produce.Should be noted that and also may use other to produce artificial reference voltage V
MIDAMethod.
The output of this differential amplifier 151 drives a disconnection (pull-down) equipment 155.According to preferred embodiment, this off device is a nmos pass transistor, can also use miscellaneous equipment although be to be understood that.The source electrode of nmos pass transistor 155 is connected to ground, and the drain electrode of nmos pass transistor 155 is connected to reference voltage V by resistance 153
MIDThe switch 159 of nmos pass transistor form is connected between resistance 139 and the ground.
150 couples of reference voltage V of following use charge/discharge control circuit
MIDDischarge.At first, switch 131 and 159 is opened, so that capacitor 135 " (float) suspends ".Preferably, switch 131 and 159 is opened simultaneously, and perhaps switch 159 is opened in switch 131 a little earlier.Provide switch 159 to have to eliminate the effect of any influence that resistance 139 may have during the discharge operation.
V
MIDAnd V
MIDABetween do not match and mean that discharge circuit 150 is configured at given reference voltage V
MIDVoltage levvl approximately be that the grid of amplifier oxide-semiconductor control transistors 155 is so that little rated current flows through transistor 155 under this initial condition of intermediate voltage (being VDD/2).Therefore, be to be understood that V
MIDAnd V
MIDABetween do not match should be as much as possible little so that make the rated current minimum that flows through transistor 155 during the outage starting stage.And little not matching guaranteed to be used to reference voltage V at charge/discharge control circuit
MIDBefore the outage, absorb this minimum current by this charge/discharge control circuit 150.
Along with transistor 155 absorption current, reference voltage V
MIDTo descend.Therefore, along with V
MIDAnd V
MIDABetween the increase of voltage difference (that is, along with V
MIDDescend), the voltage on transistor 155 grids also increases because of positive feedback path.The increase of the electric current of transistor 155 is flow through in the increase of transistor 155 grid voltages and then cause, and this again and then increased V
MIDFall off rate.
Have in the above-mentioned charge/discharge control circuit 150 two working stages or during.In first duration of work, amplifier 151, transistor 155 and resistance 153 are controlled discharge from the electric current of capacitor 135 as positive feedback path.Yet, as reference voltage V
MIDDescend when arriving at a certain, transistor 155 is opened.In case transistor 155 is opened, charge/discharge control circuit is based on the RC time constant of capacitor in parallel 135 and resistance 153 this moment just with the second mode of operation work from the current discharge of capacitor 135.
The value of resistance 153 has been set possible maximum rate of change, thereby helps and control V
MIDThe shape of attenuation curve.
As can be seen from the above, preferred embodiment is created an artificial reference voltage V
MIDA, and with this artificial reference voltage and real reference voltage V
MIDCompare.The positive feedback path of creating in discharge circuit 150 is subjected to the control of this voltage difference.
So, reference voltage V
MIDSlope form with as shown in Figure 6 in more continuous mode and with the form decay of S type waveform.In other words, t
OFFLocate unexpected slope discontinuity and be minimized or avoided, and opposite, reference voltage V
MIDDischarge with more smooth more controllable mode at first discharge regime, thus cause amplifier output to be gone up in reduction or inhibition and the prior art producing " noise made in coughing or vomiting clatter " or " crack " the relevant radio-frequency component of waveform of effect.
At reference voltage V
MIDSlope initial descend gradually and smoothly after, V
MIDVoltage levvl just descend faster at second discharge regime, promptly transistor 155 become open fully after, followed by being another progressive and smooth transition, up to its final value, this moment capacitor 135 finish its discharge process.
Therefore, in case voltage V
MIDObviously descend, promptly surpass certain a bit and since the slope discontinuity this put this transition will cause unexpected " crack ", transistor 155 becomes to be opened, and shows as quickly with voltage V
MIDDischarge, thus make capacitor 135 fully discharge with the determined speed of RC time of resistance 153 and capacitor 135.
In the superincumbent embodiment, V
MIDABe described to apart from V
MIDThe skew of rated quantity is so that help the operation of charge/discharge control circuit between the starting period.As substituting of above-mentioned embodiment, should be noted that current source 152 can be provided at Voltage Reference V
MIDAnd between the ground, be used for during the starting stage of discharge process, drawing little electric current I from capacitor 135
TRICKLEBe to be understood that, if such current source is provided, artificial reference voltage V
MIDACan be configured to and reference voltage V
MIDIdentical, rather than be offset a rated quantity.Yet, it is also understood that charge/discharge control circuit can be configured at artificial reference voltage V
MIDAWith reference voltage V
MIDBetween have a specified skew, and add a current source 152.
Fig. 7 shows an alternate embodiment of the present invention that is suitable for reducing power consumption, especially when audio devices is placed with park mode rather than cut off the power supply fully.If audio devices is cut off the power supply fully, the outage because charge/discharge control circuit 150 itself becomes after suitable process, the power consumption of charge/discharge control circuit 150 will no longer be a problem so.Yet if audio devices is placed on park mode, for example when audio frequency amplifier was temporarily cut off the power supply, the embodiment of Fig. 7 just provided adjunct circuit so, the power consumption in being used to reduce during this class.
Most of component class among Fig. 7 are similar to those assemblies of before having described about Fig. 5.Yet charge/discharge control circuit also comprises the switching device of comparator 170 forms, and this comparator 170 is connected to receive reference voltage V at its positive terminal
MID, and at its negative pole end receive threshold voltage V
RefThe output signal CS of comparator 17O is used to control first switch 172, and this first switch 172 is connected to the electrical mains of amplifier 151.The complement of output signal CS (complement), promptly CS is connected to second switch 174, and the grid that this second switch 174 is provided for transistor 155 is connected to supply voltage VDD.
Preferably, select threshold voltage V
RefIt is corresponding to being lower than V when opening fully with convenient transistor 155
MIDThe voltage levvl of voltage, but be higher than zero volt.For example, threshold voltage V
RefCan be set at V
MID/ 2, i.e. VDD/4.By this way, as reference voltage V
MIDDuring discharge (and transistor 155 become open fully after), at V
MIDReach threshold voltage V
RefThe time, the output of comparator C S is with step-down.This causes switch 172 to be opened, thereby amplifier 151 and supply voltage are disconnected.In addition because the CS step-down, so compensating signal CS uprise, thereby cause switch 174 to be closed, make the grid of transistor 155 be connected to supply voltage VDD, once more as shown in Figure 7.Therefore, switch 174 is as the bypass circuit that is used for oxide-semiconductor control transistors 155 in second duration of work when amplifier is forbidden.Be to be understood that it also may is other configuration, for example the input of comparator 170 is reversed, and signal CS and CS are used for control switch 172 and 174 by exchange.Can also adopt the alternative method that produces signal CS and CS.
In the embodiment of Fig. 7, in second duration of work of charge/discharge control circuit 150, can be minimized power consumption, and change into and use comparator 170 and switch 172,174 to continue discharge process by disconnecting amplifier 151 and interlock circuit thereof.After finishing discharge process, can also use comparator 170 and switch 172,174 so that reference voltage V
MIDKeep ground connection, for example work as voicefrequency circuit and place park mode, when not needing the power supply of pair amplifier 151 and interlock circuit thereof.
Above-mentioned embodiment has reduction and preferably stops between the reference voltage generator circuit turnoff time by V
MIDThe unwanted audio signal that causes of slope discontinuity produce do not expect " crack " advantage of sound, and still allow reference voltage generator circuit in time to discharge.
Should be appreciated that the amplifier breaker device can be known with those of ordinary skills except the bleeder circuit shown in preferred embodiments, other type reference voltage generator circuit that is used to produce reference voltage uses together.
Although described the preferred embodiment about the amplifier circuit that produces an audio output signal, the present invention can use the voicefrequency circuit that produces a plurality of audio output signals equally, for example, and stereophonic sound system as shown in Figure 8.In Fig. 8, audio system comprises and being used for from first source 115
1Produce first audio output signal 113
1First audio-frequency amplifier circuit 111 of (for example, left side output)
1, and be used for from second source 115
2Produce second audio output signal 113
2Second audio-frequency amplifier circuit 111 of (for example, right output)
2Fig. 8 is shown as has the audio frequency amplifier of being used for 5
1With 5
2Separating controlling 10
1With 10
2Yet, should be noted that audio frequency amplifier 5
1With 5
2Can work by single common control 10.And, although Fig. 8 shows the V of separation
MID Reference voltage generator 13
1With 13
2But, audio frequency amplifier 5
1With 5
2Can work by single common reference voltage generator 13.Should be appreciated that whether to comprise one or two V according to the system of Fig. 8
MID Reference voltage generator 13
1With 13
2Adopt single or two amplifier power-down circuits of the present invention.
In addition, the present invention can use together with audio system shown in Figure 9, and this audio system is (for example, the Dolby of the system that a plurality of outputs are arranged that has as use in the home theater application about a kind of
TMPro logic 5.1).Single V
MID Reference voltage generator 13 and single control logic 10 have been shown as a plurality of audio frequency amplifiers 5 of control
1To 5
N, each is all based on input signal 115
1To 115
NSeparate output signals 113 is provided
1To 113
NShould be noted that the separation buffer device 14 among Fig. 9
1To 14
NCan also be replaced by single buffer 14.
Figure 10 and 11 shows and wherein can use other typical case of the present invention to use.Figure 10 shows a kind of system, and wherein the N input signal is shown as from such as Dolby
TMObtain in the decoder of decoder, this decoder is used for the time division multiplexing audio signal from DVD is decoded.Figure 11 shows a kind of system, and wherein N signal from decoder is imported into down-conversion mixer, forms signal 1 ＇ to N ＇ (N ＇＜N) wherein so that signal 1 to N mixes.For example signal 1 to N can be six signals relevant with household audio and video system, and signal 1 ＇ to N, can be a left side and the right stereophonic signal that is used to produce stereo output signal 1 ＇ to N ＇.
It should be understood by one skilled in the art that preferred embodiment in describing PMOS and the reference of nmos pass transistor can realize by other switching device that comprises bipolar devices, and can in other configuration that identical final result is provided, realize.
Amplifier breaker device according to the present invention can be used for audio devices, this audio devices comprises, for example portable audio, Earphone Amplifier, headphone, communicator (for example mobile phone), audio device in car, and other application in a large number.
It should be noted that above-mentioned embodiment explanation rather than restriction the present invention, and those of ordinary skills can design the alternate embodiment that does not much depart from the claims scope.Word " comprises " not getting rid of and exist to remove those elements listed in the right requirement or element or the step the step." one " does not get rid of a plurality of, and the function of the plurality of units put down in writing in the claim can be realized in discrete component or other unit.Any reference marker in the claim will not be interpreted as limiting its scope.
Claims (41)
1. amplifier breaker device that is used for reducing the voicefrequency circuit transient signal, this voicefrequency circuit comprises the reference voltage generator circuit that is used to produce reference voltage, this reference voltage generator circuit comprises the capacitor that is used for reference voltage is maintained the expectation voltage levvl, and this device comprises:
Be used to control the charge/discharge control circuit of this reference voltage generator circuit outage manipulate;
This charge/discharge control circuit comprises the amplifier with positive feedback path that is used to control from the electric current of this capacitor.
2. device according to claim 1, wherein this charge/discharge control circuit comprises the transistor unit that is connected between described reference voltage and the ground, and the amplifier that wherein has a positive feedback path is configured to the flow velocity that control flows is crossed the electric current of described transistor unit.
3. device according to claim 2, the amplifier that wherein has positive feedback path comprises differential amplifier, this differential amplifier is connected the reference voltage that just is being controlled in first input to receive, and second reference voltage in second input.
4. according to claim 2 or 3 described devices, also comprise the resistance device that is connected in series with described transistor unit.
5. device according to claim 4, wherein said charge/discharge control circuit are configured and are controlled as between the first phase with the first mode of operation work, and the second phase with the second mode of operation work.
6. device according to claim 5 is wherein determined during described first mode of operation electric current from capacitor by described transistor unit and positive feedback path.
7. according to claim 5 or 6 described devices, wherein determine during described second mode of operation electric current from capacitor by described resistance device.
8. according to each described device in the claim 5 to 7, the amplifier that forbidding had positive feedback path when wherein said charge/discharge control circuit was configured to work with second mode of operation in the described second phase.
9. device according to claim 8, wherein said charge/discharge control circuit comprise and are used in the described second phase, have the bypass circuit that the amplifier of positive feedback path is controlled described transistor unit when disabled.
10. according to each described device in the claim 5 to 9, also comprise the switching device that is used for switching to described second mode of operation from described first mode of operation.
11. device according to claim 10, wherein said switching device are suitable for switching to described second mode of operation from described first mode of operation when described reference voltage has dropped to predetermined threshold voltage.
12. according to claim 10 or 11 described devices, wherein said switching device comprises comparator device, this comparator device is connected reference voltage and the threshold voltage in second input that just is being controlled in first input to receive.
13., wherein before outage, be configured to the voltage levvl of just controlled reference voltage the voltage levvl of described second reference voltage basic identical according to each described device in the claim 3 to 12.
14., wherein before outage, the voltage levvl of described second reference voltage is configured to than the voltage levvl of just controlled reference voltage skew is arranged according to each described device in the claim 3 to 12.
15., also comprise the current source that is used for providing to described charge/discharge control circuit initial trickle charge in the starting stage of discharge operation according to claim 13 or 14 described devices.
16. according to each described device in the aforementioned claim, wherein said reference voltage generator circuit comprises the bleeder circuit that is used to produce reference voltage, this bleeder circuit comprises first and second resistance devices between being connected power supply and ground connects, and be connected and connect capacitor between the common node of described first and second resistance.
17. device according to claim 16, also comprise first resistance device that is connected described bleeder circuit and first switching device between the supply voltage, and being connected second resistance device of described bleeder circuit and the second switch device between the ground, described first and second switching devices can be operated so that isolate described bleeder circuit between turnoff time.
18. method that reduces transient signal in the voicefrequency circuit, this voicefrequency circuit comprises the reference voltage generator circuit that is used to produce reference voltage, this reference voltage generator circuit comprises the capacitor that is used for reference voltage is maintained the expectation voltage levvl, and this method comprises the steps:
Be provided for controlling the charge/discharge control circuit of described reference voltage generator circuit outage manipulate;
The amplifier that use has a positive feedback path is controlled the electric current from the capacitor of described reference voltage generator circuit.
19. method according to claim 18 is further comprising the steps of: between described reference voltage and ground, provide transistor unit, and make amplifier dispose positive feedback path, cross the flow velocity of the electric current of described transistor unit with control flows.
20. according to claim 18 or 19 described methods, the amplifier that wherein has positive feedback path comprises differential amplifier, connect this differential amplifier and just be controlled in first reference voltage of importing to receive, and second reference voltage in second input.
21., also comprise the step that resistance device and described transistor unit are connected in series according to claim 19 or 20 described methods.
22. method according to claim 21, wherein said charge/discharge control circuit are controlled as between the first phase with the first mode of operation work, and the second phase with the second mode of operation work.
23. method according to claim 22 is wherein determined during described first mode of operation electric current from capacitor by described transistor unit and positive feedback path.
24., wherein determine during described second mode of operation electric current from capacitor by described resistance device according to claim 22 or 23 described methods.
25., comprise that also forbidding has the step of the amplifier of positive feedback path when working with second mode of operation in the described second phase according to each described method in the claim 22 to 24.
26. method according to claim 25 also comprises being provided for having the step that the amplifier of positive feedback path is controlled the bypass circuit of described transistor unit when disabled in the described second phase.
27., also comprise the step that is provided for switching to the switching device of described second mode of operation from described first mode of operation according to each described method in the claim 22 to 26.
28. comprising when described reference voltage has dropped to predetermined threshold voltage, method according to claim 27, wherein said switch step switch to described second mode of operation from described first mode of operation.
29. according to claim 27 or 28 described methods, wherein said switching device comprises comparator device, connects this comparator device to receive reference voltage and the threshold voltage in second input that just is being controlled in first input.
30. according to each described method in the claim 20 to 29, also be included in before the outage, the voltage levvl of described second reference voltage be configured to the essentially identical step of voltage levvl with just controlled reference voltage.
31. according to each described method in the claim 20 to 29, also be included in before the outage, the voltage levvl of described second reference voltage be configured to have than the voltage levvl of just controlled reference voltage the step of skew.
32., also be included in the step that initial trickle charge was provided to described charge/discharge control circuit during starting stage of discharge operation according to claim 30 or 31 described methods.
33. according to each described method in the claim 18 to 32, wherein said reference voltage generator circuit comprises the bleeder circuit that is used to produce reference voltage, this bleeder circuit comprises first and second resistance devices between being connected power supply and ground connects, and be connected and connect capacitor between the common node of described first and second resistance.
34. method according to claim 33, further comprising the steps of: as between first resistance device of described bleeder circuit and supply voltage, to provide first switching device, and between second resistance device of described bleeder circuit and ground, provide the second switch device, and operate described first and second switching devices between turnoff time, to isolate described bleeder circuit.
35. an audio devices, this audio devices comprise according to each amplifier breaker device in the claim 1 to 17.
36. a portable audio, this portable audio comprise according to each amplifier breaker device in the claim 1 to 17.
37. an Earphone Amplifier, this Earphone Amplifier comprise according to each the amplifier breaker device or the part of this amplifier breaker device in the claim 1 to 17.
38. a headphone, this headphone comprise according to each amplifier breaker device in the claim 1 to 17.
39. a communicator, this communicator comprise according to each amplifier breaker device in the claim 1 to 17.
40. an audio device in car, this audio device in car comprise according to each amplifier breaker device in the claim 1 to 17.
41. a reference voltage signal that is used for voicefrequency circuit uses according to each amplifier breaker device in the claim 1 to 17, and this reference voltage signal is configured to have " S " type shape.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0617196A GB2441360B (en) | 2006-08-31 | 2006-08-31 | Amplifier apparatus and method |
| GB0617196.1 | 2006-08-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101136609A true CN101136609A (en) | 2008-03-05 |
Family
ID=37137136
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2007101476176A Pending CN101136609A (en) | 2006-08-31 | 2007-08-31 | Amplifier apparatus and method |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US8208658B2 (en) |
| CN (1) | CN101136609A (en) |
| GB (1) | GB2441360B (en) |
| TW (1) | TW200822533A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102045630A (en) * | 2009-10-16 | 2011-05-04 | Nxp股份有限公司 | Capacitive sensor |
| CN103001594A (en) * | 2011-09-16 | 2013-03-27 | 意法半导体研发(深圳)有限公司 | Amplifying circuit |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110007912A1 (en) * | 2009-07-07 | 2011-01-13 | Mediatek Singapore Pte. Ltd. | Double integral method of powering up or down a speaker |
| CN102082983B (en) * | 2009-11-26 | 2013-11-06 | 鸿富锦精密工业（深圳）有限公司 | Crackle suppression circuit |
| WO2013017913A1 (en) * | 2011-08-01 | 2013-02-07 | Freescale Semiconductor, Inc. | Signalling circuit, processing device and safety critical system |
| JP6123569B2 (en) * | 2013-08-15 | 2017-05-10 | 株式会社ソシオネクスト | Voltage generation circuit and control method of voltage generation circuit |
| US9584104B2 (en) | 2014-03-15 | 2017-02-28 | Nxp Usa, Inc. | Semiconductor device and method of operating a semiconductor device |
| CN104879294B (en) * | 2015-04-14 | 2017-12-26 | 中国农业大学 | A kind of water pump transient signal analytical equipment and method |
| DK3343956T3 (en) * | 2016-12-30 | 2021-05-03 | Sonion Nederland Bv | A circuit and a receiver comprising the circuit |
| CN109817238B (en) * | 2019-03-14 | 2021-08-24 | 百度在线网络技术（北京）有限公司 | Audio signal acquisition device, audio signal processing method and device |
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| JPS5591211A (en) * | 1978-12-28 | 1980-07-10 | Matsushita Electric Ind Co Ltd | Preventing circuit for click noise occurrence |
| JPS59156007A (en) * | 1983-02-25 | 1984-09-05 | Hitachi Ltd | Amplifier circuit |
| US5642076A (en) * | 1995-01-31 | 1997-06-24 | National Semiconductor Corporation | No turn-on pop noise amplifier |
| US6522278B1 (en) * | 1997-09-30 | 2003-02-18 | Cirrus Logic, Inc. | Digital-to-analog converter with power up/down transient suppression and automatic rate switching |
| US6373954B1 (en) * | 1997-10-14 | 2002-04-16 | Cirrus Logic, Inc. | Single-chip audio circuitry, method, and systems using the same |
| US6775387B1 (en) * | 1999-11-30 | 2004-08-10 | Texas Instruments Incorporated | Three-step ramped reference to reduce popping noises on audio circuit |
| US7254244B2 (en) * | 2003-07-28 | 2007-08-07 | Sigmatel, Inc. | Pop and click reduction using DAC power up and power down processing |
| EP1899974B1 (en) * | 2005-06-29 | 2013-06-12 | Analog Devices, Inc. | Improved charge/discharge control circuit for audio device |
-
2006
- 2006-08-31 GB GB0617196A patent/GB2441360B/en active Active
-
2007
- 2007-08-24 US US11/892,641 patent/US8208658B2/en active Active
- 2007-08-24 TW TW096131376A patent/TW200822533A/en unknown
- 2007-08-31 CN CNA2007101476176A patent/CN101136609A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102045630A (en) * | 2009-10-16 | 2011-05-04 | Nxp股份有限公司 | Capacitive sensor |
| CN102045630B (en) * | 2009-10-16 | 2013-09-18 | Nxp股份有限公司 | Capacitive sensor |
| CN103001594A (en) * | 2011-09-16 | 2013-03-27 | 意法半导体研发(深圳)有限公司 | Amplifying circuit |
| CN103001594B (en) * | 2011-09-16 | 2017-07-18 | 意法半导体研发(深圳)有限公司 | Amplifying circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2441360A (en) | 2008-03-05 |
| GB2441360B (en) | 2011-09-21 |
| US8208658B2 (en) | 2012-06-26 |
| US20080069376A1 (en) | 2008-03-20 |
| TW200822533A (en) | 2008-05-16 |
| GB0617196D0 (en) | 2006-10-11 |
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Application publication date: 20080305 |